Distributor tube construction



Aug. 19, 1952 LABlN DISTRIBUTOR TUBE CONSTRUCTION Filed Nov. 10, 1947 IN VEN TOR. fM/LE LAB/ N A 7' T ORNEY Patented Aug. 19, 1952 DISTRIBUTOR TUBE CONSTRUCTION Emile Labin, New York, N..Y., assignor toInternationalStandard Electric Corporation, New York, N. Y., a, corporation of Delaware Application November 10, 1947, Serial No. 785,007, V

' 12 Claims. 1

This invention relates to distributor tube construction particularly the type using secondary electron emissive electrodes.

Heretofore, there has been proposed cathode ray tube distributors in which the beam is deflected to pass through openings in an aperture plate and strike secondary emissive target elements, the aperture plate itself serving as the collector. The aperture plate also serves to collect primary electrons of the beam when they are not being directed through the apertures in said plate toward the target electrodes to thus prevent unwanted secondary emission and other undesirable effects in the tube. Since the aperture plate serves as the collector for secondary electrons emitted from the target elements, the aperture plate is at a higher positive potential than the target elements, thus producing a field which is in a reverse direction and opposes the flight of the primary electrons in the beam towards the target elements. Likewise the secondary electrons also move in a direction to produce a similar reverse field. These fields under certain circumstances, may be sufficiently great to prevent at least a part of the electron beam from passing through the aperture plate thus causing skipping or may result in a defocussing of the electron beam with danger of cross-talk as other deleterious effects, before it passes through said plate.

An object of the present invention is the provision of an improved distributor tube of the cathode ray type using secondary electron emission electrodes, particularly one avoiding the foregoing defects.

In accordance with a feature of the present invention, the aperture plate is used solely as a shield with a single or plurality of secondary electron emitting electrodes arranged behind the apertures and the collector electrodes arranged behind the secondary emitting electrodes. Consequently when proper voltage is applied to said device, the fields are such as to accelerate the primary electrons causing them to pass readily through the aperture plates and to remain focussed. Additional means are employed in accordance with another feature of the present invention to prevent the secondary emitting electrons from interacting in the various channels.

The above-mentioned and other features and objects of this invention will become more apparent and the invention itself, though not necessarily defined by said features and objects, will be bestunderstood by reference to the following description of embodiments of the invention 2 taken in connection with the accompanying drawings, wherein:

Fig. 1 is a schematic diagram of a distributor tube embodying my invention, indicating the application of the potentials to the secondary emitting and collector electrodes; and

Figs. 2 and 3 are schematic diagrams of modified forms of a distributor tube embodying my invention.

Referring now to Fig. l, the distributor tube I may include an evacuated envelope 2, within which is arranged an electron gun 3 for producing an electron beam which is preferably defiected bymeans of a set of deflection plates 4. An aperture plate'S is arranged in front of the beam and preferably has'a plurality of apertures 6, 1, etc. which are so arranged that as the beam is deflected, it passes from one aperture to the other. The apertures may be arranged in a circle and the beam may likewise be deflected in a circle by applying suitable voltages to the deflection plates such as, for example, by applying voltages of the same frequency but 90 out of phase separately to the horizontal and vertical deflection plates respectively. Behind the aperture plate 5 may be mounted a foraminous member, for example in the form of a screen 8, which is suitably coated witha high ratio secondary electron emitting material so as to form a secondary emitting electrode and adapted to emit electrons when the beam passes through the aperture plate and strikes portions of the surface thereof. On the other side of the screen 8 opposite the side on which the aperture plate is arranged, are mounted a plurality of collector electrodes or anodes 9, l0, etc., each of said anodes being aligned with one of the apertures in aperture plate 5. Thus for example, anode 9 is aligned with aperture 6 and anode I ll is aligned with aperture 1. -When the beam passes through aperture 6, it strikes the screen 8 giving off secondary electrons which are collected by anode 9, the spacing between the anodes being such that anode ID will pick up substantially none of these electrons.

The anodes 9 and Ill are maintained at higher positive potentials than the screen 8 in order that a plurality of screens l4, l5, etcu, equal in number to the number of apertures, the number of collecting anodes, and the number of distributing channels. Each of the screens l4, 15, etc., is surrounded by a shield which may be in the form of a cylinder IS, the cylinder [6 serving to focus and direct the secondary electrons in a line and prevent, them from moving out of the path assigned to their channel; To produce higher amplification, additional screens such as H, l8, etc., may be arranged behind screens I4, 1

l5, etc., in line therewith so as to be struck by the secondary electrons emitted by'the first row of screens including l4, I and'toemi-t a, greater amount of electrons. Screens IT, and '18 etc.,

are likewise surrounded by shields similar to l6. Additional rows of screens, as

electrons due to. theshields, the tendency toward cross-talk is reduced. :High amplification :is obtained because of the number of secondary emitting electrodes aligned with each aperture in the aperture plate each adding to the total-output current reaching each anode. Proper direct current potentials are applied from any suitable source 23.

"While in the foregoing .two distributor tubes,

screens coated -.v'v-ith secondary emissive .materials have been' uti'lized, it willbeapparent that other "secondary iemittin'g arrangements may be employed. For example, referringLnow to Fig. 3, there is-arr'angedbehindthe aperture plate '5 a plurality 'of aligned hollow truncated cones or funnels a l', 25,- etc., equal in number .to the number of apertures as for example, with cones 24 and 25 aligned with apertures'fi and! etc. The inner surfacesof thetruncated hollow cones are coated with-a suitable high ratio secondary emitting electron material adapted to be impinged upon as the beam passes'through the apertures of said plate B and causing. the emission ofsecondary electrons which are picked up byanodes iii, 2T, etc., one"for each of the' channels, each anode-being aligned'with its secondary emitting cone. Suitable potentials are applied as indicated ='from' any suitablesource '28-so as to cause the secondary electrons to pass from the rear end of the cone toward the anode.

It'will'be seen, in each of 'the embodiments shown, that the field is "in a direction such as to accelerate theprimary electrons so that there is no difiiculty'in regard to the primary electrons passing through their aperture. The primary electronbeam is'not defocussed but tends 1. A distributor tube construction comprising 7 an evacuated envelope-having 'mounted therein means for producingan electron beam, means 4 for deflecting said beam along a path defining a given closed curve, beam control means positioned to intercept the beam intermittently along its closed path to pass said beam only at predetermined deflection angles, secondary electron emitting means mounted for impingement by the beam passed at said angles and a plurality of separate mutually spaced output anodes each mounted in an array having a shape similar' to that of said closed curve to receive secondary emitted electrons from said secondary electron emitting means as the beam reaches a corresponding one of said angles.

12.- A distributor tube construction according to claim, 1 wherein said beam control means is .mounted between the beam producing means and the secondary electron emitting means.

3. A distributor tube construction according to claim 1 wherein said secondary emitting means is mounted between said anodes and said beam control means.

4. A distributor tube construction according to claim 1 wherein said beamcontrol means is mounted between the beam producing means and secondary electron emitting means, and said secondary emittin means is mounted between said anodes and said beam control means.

5. A distributor tube construction according to claim 1 wherein said secondary electron emitting means is comprised of a metallic foraminous member coated with high ratio secondary electron emitting material and having the anodes mounted adjacent thereto to different portions of the surface thereof.

6. A distributor tube construction according to claim 1 whereingsaid secondary electron emitting meansis comprised'of aplurality of screens each aligned with oneof said anodes.

"'7. A distributor tube construction according to claim'l' wherein said secondary electron emitting means. :comprisc-d of a plurality of funnelshaped members each mounted in front of one of said .anodesand having the interior surface thereof "coated with .a .high ratio secondary electron emitting :material. l

.8. A distributor tube construction comprising an evacuated envelope having mountedztherein :means for producing an electron beam, means for deflecting said'beam'along a generally circular path, an aperture plate mounted to intercept the beam intermittently and having a plurality of circularly :disposecl apertures therein through which the beam passes as itis deflected .over the apertured platealon'g said circular path, secondary electron emitting means mountedin line with the apertures and adapted to be impinged upon by theprimary electrons of thebeam'as they pass throughsaid apertures,and a plurality of anodes mounted in agenerally circular array behind said secondary electron emitting 'means. and each aligned with one of said aperturesrand adapted to collect thesecondary electrons emitted by said vsecondary.electron emittingmeans in response to the passage of said beam through a corresponding one of .said apertures.

19. Aidistributor-tube construction according to claim 8, whereinsaid .secondary electron emitting means 'iszcomprisedof; a screen coated with-high "ratio secondary electron emitting .material, and

mountedbetweemsaidranodes and said apertured plate.

.10. A distributortube construction according to claim- .8. wherein said secondary electron emitting means includes a plurality of rows of screens,

each row consisting of a plurality of small screens each aligned with one of the apertures, each of the screens coated with a high ratio secondary electron emitting material.

11. A distributor tube construction according to claim 8 wherein said secondary electron emitting means includes a plurality of rows of screens, each row consisting of a plurality of small screens each aligned with one of the apertures, each of the screens coated with a high ratio secondary electron emitting material, and further including shielding means arranged around each of said screens to prevent the secondary electrons from moving out of the path leading to their corresponding anode.

12. A distributor tube construction according to claim 8 wherein said secondary electron emitting means is comprised of a plurality of tunnelshaped hollow members each having their interior surface coated with a high ratio secondary electron emitting material with the larger end 91' each iuimel facing toward the corresponding aperture of said plate and the smaller end facing toward the associated anode.

EIVIILE LABIN.

REFERENCES CITED The following references are of record in the file or this patent:

UNITED STATES PATENTS Number Name Date 2,086,904 Evans July 13, 193'! 2,185,684 Bennett Jan. 2, 1940 2,204,055 'Skellett June 11, 1940 2,250,528 Gray July 29, 1941 2320,1846 Strutt et a1. May 20, 1947 2,452,157 Sears Oct. 26, 1948 2362396 Ransom Mar. 1, 1949 2,468,085 Labin et a1 Apr. 26, 1949 

